My truck is on its 4TH REAR DIFF

There's a lot of air space under the bed that makes noise from 55-57mph and other speeds. I'll bet dollars to donuts it's not the diff. (For the OP). Aaand after rereading maybe scored bearings. But too many owners think a sprung truck is as silent as a Lexus GS.

 

I can tell you when i recently got more cosmoline to finish coating the underneath of the cab and bed the truck now feels very tight and quieter running. Imo, its a win win.

 

They replaced your diff 3 times?!

where’s your dealership located? Asking for a friend

 

I would take it to a reputable differential shop and have them look at it.

 

AS other have said, the driveline needs a better diagnosis. If the diff is failing there is a reason.

 

Toyota does not rebuild anything they put a complete 3rd member in as no one at the dealer knows how to rebuilt one!
As Choano said something else is bent or not right. Bent axle, scored or messed up bearings outer or inner, or perhaps the factory units (3rd member) or not properly setup to start with. Yep time for Toyota to replace the entire rear or go to a good trans/diff shop.
Sorry sucks dealing with that crap and if no fix dump it fast as stated prices are up.

 

I would get the extended warranty and then get rid of the truck soon as the warranty is about to end.

 

This was one of the many reasons I got rid of my 2016 as soon as the warranty ran out. They never could get the rear diff (or 2 other chronic issues) fixed. Took my high trade in value and moved on.

 

Toyota Knoxville

 

Thanks for all the replies -- update is that I took the truck back to the dealership again, they are going to bring in a Toyota engineer and do a proper diagnosis, they may replace entire rear axle and they profusely apologized for not addressing the root issue sooner, recognized that they were obviously treating symptoms. The service manager acted like it was a pretty big fuck up and obviously Toyota doesn't want to be paying for a new diff every thousand miles, this will be number 5... That said, Hopefully they actually fix the issue this time, if they come back with the same old bullshit I'll just sell the truck to Carvana, I ran a quick quote so am considering that route if they can't fix it -- I could just get a 2020 that'll track me and tell Amazon everywhere I go

 

I am always surprised at how quickly people say “lemon law” on this forum........like that is actually going to happen.

If you’ve blown three diffs there is an alignment issue in the driveline that is either causing excess vibration, or undue lateral pressure on the bearings.

You need a more skilled mechanic, not a lawyer.

 

Unfortunately, I have a feeling the Toyota engineer is going to come out and tell you that the noise is "normal" and deny and further warranty claims regarding that noise. I have a similarly excellent Toyota dealership that replaced multiple headlights for me but after a couple they said they had to get Toyota corporate involved. They ordered the headlight, had it all ready to install, and corporate told them they could do whatever they want but that the condition would not be covered by warranty (a ton more info on that but thats the basic jist of it).

Good luck and I hope they take care of you!

 

He said they replaced the carrier bearing assembly not the entire differential. Replacing the entire differential would require replacing the axle unless you consider the differential to not include the differential housing. Please correct me if I am wrong.

 

He said carrier assembly.

 

A whining sound during deacceleration is from excessive pinion bearing preload

A whining sound on acceleration is from a worn pinion bearing

A low frequency rumbling sound above 20mph is indicative of a bad carrier bearing


Also improper backlash or contact pattern on the ring gear can cause problems

This is my Ford 9" center section , notice the contact patch on the yellow grease .This is a perfect pattern that will allow trouble free operation




.

 

OP .... I bet if you took your truck to qualified driveline shop and have the build and assemble a new 3rd member your rear axle problems would be gone

 

i brought my 17 OR brand new and at 300 miles I start noticing this sound at around 45 to 50 mph. With the windows up I did not hear anything. After putting 65,000 miles on the truck I never heard this sound again. I even look under the truck to inspect the rear diff and I don’t see any leaks at all I now have 96,000 miles and still no noise from the diff. Never had the dealer look at it.

 

Or a Ford 9" rear with 35 spline axles that is capable of supporting 2k hp

 

I forgot to mention in my previous post , that a howl or whining noise that is heard over a wide mph range is indicative to a worn ring and pInion gear

The cause of this is either improper ring and pinion backlash " contact patch" or soft metal gears

 

I agree lemon laws don’t cover mechanic stupidity.